P3D Re: Differential Focus

[Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Wed, 17 Mar 1999
>From: "Dr. George A. Themelis" <DrT-3d@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
>.............
>Ray Moxom writes:
>
>>I suggest that Differential Focus has its place in stereo photography. One
>>of the top exhibition stereo photographers uses Differential Focus to
>>optimise film speed, shutter speed & DOF for many of his action shots. He
>>slightly varies the focus of the tele lenses on his twin rig. The results
>>are impressive and have taken out many International awards.
>...........

>>From personal experience, when using longer focal length lenses, focusing
>is critical and "differential focusing" (another term for failing to match 
>focusing in the two manual lenses? :-)) can drive you crazy and spoil the 
>result of an otherwise good stereo picture.  While the effect is not too 
>great to be seen in projection (hence awards may come in) it is certainly 
>noticeable and disturbing in the viewer.
>
>Thanks!
>
>George Themelis
>

*****  I side with George on this differential focusing routine. I read with
interest how it balances out somehow and the mind extracts the detailed
information as needed. I'm glad the mind is capable of doing this, but in my
work with stereo images, I've always found that while the mind is very
flexible, providing it with two very crisp clear and very focused images
makes a difference. It's like the difference between dirty glasses and
freshly cleaned ones. You can see adequately from them either way, but the
extra punch through the cleaned glasses makes it worth doing.

I'll stick with technology that doesn't compromise with systems like
differential focus. 

Larry Berlin

Email: lberlin@xxxxxxxxx
http://www.sonic.net/~lberlin/
http://3dzine.simplenet.com/


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